(function(){
    var form = document.querySelector(".form-signin");

    form.addEventListener("submit", validate);

    function validate(e) {
        e.preventDefault();

        var form = this
            , inputs = form.querySelectorAll("[data-error]");
        var act = $("#act").val(); // Вот нужный мне act
        clear(inputs, function() {
            checkIsEmpty(inputs);
        });

        function checkIsEmpty(inputs, act) {
            var isEmpty = false;

            for (var i = 0; i < inputs.length; i++) {
                var input = inputs[i];

                if (input.value.trim() === "") {
                    isEmpty = true;
                    markInput(input);
                }
            }

            var inputsTypePassword = form.querySelectorAll("[type='password']")
                , checkPassComplete = checkPassword(inputsTypePassword, act);

            if (!isEmpty && checkPassComplete) {
                var username = document.getElementsByName("username")[0].value;
                var password = document.getElementsByName("password")[0].value;
                var dataString = 'username=' + username + "&password=" + password + "&act=" + act;
                alert(act); // скрипт срабатывает, но act передаётся undefined
                $.ajax({
                    url: "ajaxjs.php",
                    type: "POST",
                    data: dataString,
                    cache: false
                });
                //window.location = "index.php";
            }
        }

        function markInput(input) {
            input.classList.add("error");
            var text = input.getAttribute("data-error");

            if (!text) return;

            var div = document.createElement("div");

            div.textContent = text;
            div.className = "error-text";
            input.parentNode.appendChild(div);
        }

        function clear(inputsItem, callback) {
            for (var i = 0; i < inputsItem.length; i++) {
                var input = inputsItem[i]
                    , parent = input.parentNode
                    , message = parent.querySelector(".error-text");

                input.classList.remove("error");
                if (message) parent.removeChild(message);
            }

            if (callback) callback();
        }

        function checkPassword(inputsTypePassword, act) {
            if (!inputsTypePassword) return true;
            clear(inputsTypePassword);

            var isValid = true
                , firstPassInput = inputsTypePassword[0]
                , pattern = firstPassInput.value.trim()
                , text = firstPassInput.getAttribute("data-wrong-pass")
                , parent = firstPassInput.parentNode;
            if (inputsTypePassword.length > 1) {
                var input = inputsTypePassword[1];

                if (input.value.trim() !== pattern  ||  input.value.trim() === "") {
                    isValid = false;
                }

                if (!isValid) {
                    for (var k = 0; k < 2; k++) {
                        var errorInput = inputsTypePassword[k];
                        var value = errorInput.value;
                        markInput(errorInput);
                        if (value !== "") {
                            parent.querySelector(".error-text").textContent = text;
                        }
                    }
                }
            }
            return isValid;
        }


    }
}());